1. Technical Field
This invention relates in general to a temperature indicating device providing a visual indication of when a certain temperature has been reached and, more particularly, to a multi-stage multi-temperature temperature indicating device for use in cooking foods providing a visual indication of specific multiple temperatures, when a first temperature has been reached and then when a second temperature has been reached, or as a pre-indicator that the end point temperature will be reached within a specific time.
2. Prior Art
Temperature indicating devices are known and have been used for measuring internal temperatures when cooking meat, poultry and the like. Such temperature indicating devices typically include a barrel-shaped housing and an indicator rod retained in the barrel by a fusible material. When a predetermined temperature is reached, the fusible material softens, releasing the indicator rod from the barrel to provide a visual indication that the product is fully cooked. With the temperature indicating device, a consumer may safely prepare meat or poultry without overcooking the product. U.S. Pat. Nos. 4,748,931, 5,799,606, and 5,988,102 disclose representative examples of such temperature indicating devices.
To ensure the temperature indicating device provides a reliable, accurate indication of the internal temperature of the product, the fusible material must securely retain the indicator rod within the housing until the temperature indicating device has been heated to a predetermined temperature. Most current temperature indicating devices indicate only one temperature, namely the temperature at which the temperature indicating device is designed to activate. However, devices that can indicate two temperatures are known, and U.S. Pat. No. 4,421,053 discloses such a temperature indicating device that indicates two temperatures.
There has been a very high interest in the cooking industry for a temperature indicating device that communicates cooking progression. For example, it would be advantageous for cooks to know approximately when the main course (the turkey or the roast beef, for example) will be ready. Thus, such a device could indicate approximately when the main course will be ready by giving a first indication at a first approximate temperature (or approximate time prior to final activation), allowing the cook time to prepare other dishes for the meal. This device could assist the cook in knowing when the device is going to activate indicating that the food is done cooking. This device also could indicate when a first temperature has been reached and then indicate when a second, higher, temperature has been reached, such that the cook is informed that there is a certain limited time period before the food is thoroughly cooked. This device further could assist cooks in knowing when the more difficult “medium” (as opposed to rare or well-done) temperatures have been reached. However, to date, the industry has not been able to provide a satisfactory disposable temperature indicating device with precise multiple temperature indications. The present invention is meant to address these needs for a disposable precision multiple temperature indicating device.